Passenger safety restraint with pretensioner

Abstract

The present invention provides a pneumatically operable indication of when a pretensioner has operated in a vehicle passenger safety restraint system. The indication may be audible or visible, for example an inflatable brightly coloured balloon in the vehicle trim or a whistle or a flag. Such an indication ensures that the vehicle owner knows when the pretensioner feature of his vehicle is not available for a subsequent crash condition so that he can seek re-setting or servicing of the pretensioner at the earliest opportunity.

We claim: 
     
       1. A vehicle passenger safety restraint comprising a seat belt deployable to resist movement of an occupant from a desired position in a seat in the event of a crash and further comprising pretensioner means operable to tighten the seat belt at a early stage of the crash, wherein pneumatically operable indication means are provided for indicating that the pretensioner means has operated. 
     
     
       2. A vehicle passenger safety restraint according to claim 1, wherein the pretensioner is operable by a pyrotechnic device. 
     
     
       3. A vehicle passenger safety restraint according to claim 1, wherein the pretensioner is operable by a compressed gas storage device. 
     
     
       4. A vehicle passenger safety restraint according to claim 1, wherein the indication means is operable to produce an audible indication signal. 
     
     
       5. A vehicle passenger safety restraint according to claim 1, wherein the indication means is operable to produce a visible indication signal. 
     
     
       6. A vehicle passenger safety restraint according to claim 1, wherein the indication means is operable by gas produced or released during operation of the pretensioner. 
     
     
       7. A vehicle passenger safety restraint comprising a seat belt deployable to resist movement of an occupant from a desired position in a seat in the event of a crash; pretensioner means operable to tighten the seat belt at an early state of the crash, pneumatically operable indication means for indicating that the pretensioner means has operated, the indicating means operable by the gas produced or released during operation of the pretensioner; wherein the indication means comprises a flag operable to be moved by gas produced or released during operation of the pretensioner means, from a position in which it is not visible, into a position where it is visible to a passenger and indicate operation of the pretensioner.   
     
     
       8. A vehicle passenger safety restraint comprising a seat belt deployable to resist movement of an occupant from a desired position in a seat in the event of a crash; pretensioner means operable to tighten the seat belt at an early state of the crash, pneumatic means for producing a positive pressure by gas produced or released during the operation of the pretensioner; pneumatically operable indication means for indicating that the pretensioner means has operated, the indicating means operable by the gas produced or released during operation of the pretensioner; wherein the pretensioner has a piston movable within a cylinder and wherein the pneumatic means includes a portion of the cylinder provided with a narrow aperture at the end to which the piston moves during the pretensioning operation so that during pretensioning an elevated pressure signal is produced at the aperture.   
     
     
       9. A vehicle passenger safety restraint according to claim 8, wherein a whistle is connected to the aperture. 
     
     
       10. A vehicle passenger safety restraint according to claim 8 comprising a turbine nozzle connected to the aperture to activate a rotatable siren-whistle wheel. 
     
     
       11. A vehicle passenger safety restraint according to claim 8 wherein the indication means includes audible means for producing an audible indication signal and further comprises reservoir means connected between the aperture and the audible means to prolong the length of the sound produced.   
     
     
       12. A vehicle passenger safety restraint according to claim 7 wherein the flag comprises a flexible inflatable element operable to be inflated by pneumatic pressure on operation of the pretensioner to adopt a prominently visible inflated condition. 
     
     
       13. A vehicle passenger safety restraint according to claim 12, wherein the flexible inflatable element is brightly coloured and is mountable in an aperture in the vehicle trim. 
     
     
       14. A vehicle passenger safety restraint according to claim 12, comprising a one-way valve connected upstream of the flexible inflatable element. 
     
     
       15. A vehicle passenger safety restraint according to claim 9 further comprising reservoir means connected between the aperture and the indication means to prolong the length of the sound produced. 
     
     
       16. A vehicle passenger safety restraint according to claim 10 further comprising reservoir means connected between the aperture and the indication means to prolong the length of the sound produced. 
     
     
       17. A vehicle passenger safety restraint according to claim 7 comprising a one-way valve connected upstream of the flag. 
     
     
       18. The vehicle passenger safety restraint as defined in claim 7 wherein the flag is remote from the pretensioner. 
     
     
       19. The vehicle passenger safety restraint as defined in claim 12 wherein the flexible inflatable element is remote from the pretensioner. 
     
     
       20. A vehicle passenger safety restraint according to claim 8, wherein the indication means includes audible means for producing an audible indication signal.